Africa Minister Mark Malloch Brown said Britain was fully engaged in trying to bring an end to the conflict which experts say has killed hundreds of thousands people and uprooted 2.5 million, but other nations are not committed enough.

"We've got to make this plan work," Malloch Brown said of a United Nations proposal to send a joint U.N.-African Union force of 26,000 to replace a struggling AU mission which has so far failed to stem the violence in Darfur.

"It's the right plan. It just needs an awful lot of sustained political will to make it work," he told BBC radio.

"And we do feel a bit lonely out there. We're very engaged, but we don't see quite as much commitment from all governments on this."

In July, the U.N. Security Council authorised a U.N.-AU mission of up to 19,555 military personnel and 6,432 international police. Britain and France pledged in August to work to have the force deployed by the end of the year.

But U.N. peacekeeping chief Jean-Marie Guehenno has cast doubt on its deployment due to Sudan's restrictions on its movements and refusal to accept non-African troops. Western states have also not provided attack and transport helicopters.

Malloch Brown said Britain had been unable to provide any helicopters because of its military commitments in Iraq and Afghanistan, but said London had provided 75 million pounds ($155 million) to keep the interim peacekeeping force in place and would pay 8 percent of the cost of the U.N.-AU mission.

Malloch Brown said he now hoped the force would be deployed from early 2008. He described it as a "rolling deployment" that would "run through at least the first six months of next year".

"We are working both to accelerate the deployment ... and to push the rebel-government peace talks so that there is a peace to keep and these troops are not put into a situation of open conflict," he said.

"It's a very, very difficult situation. The odds are ... against its success so we have got to work to overcome that."

Malloch Brown said Britain was putting equal pressure on the Sudanese government and on rebel groups to secure a ceasefire.

"The government has promised an end to hostilities, the rebels need to match that -- and we need to get a monitoring system in place to make sure there are no ceasefire violations."

"It is really incredible that rebel leaders are not willing to come forward and talk when their peoples' welfare on the ground -- a couple of million people in camps -- depends so clearly on getting peace."